A question of style
The reaction rate of many molecules depends on their shape
Most molecules occur in several shapes, which may behave very differently. Using a sorting machine for molecules, a German–Swiss research team can now for the first time directly measure the various reaction rates of different forms of the same compound.
Artist's concept of the sorting mechanism. Conformers with a larger dipole moment (marked blue) are deflected stronger than those with a smaller dipole moment (marked red). This way, one type of conformers can be picked and lead seperately to react with the ultra cool calcium ions.
Yuan-Pin Chang/DESY
The charged rod gives rise to an inhomogenous electric field in the small slit between the rod and the trough. This field deflects conformers with varying dipole moments differently.
Jochen Küpper/DESY
Many chemical compounds have numerous so-called conformers -- different forms of a molecule in which some building blocks are spatially rearranged (rotated). "Even tiny changes in structure can greatly affect the properties of a compound," says Küpper. "We want to know how exactly the molecular structure influences chemical reactions. Different conformers can even lead to different reaction products."
To investigate these differences in more detail, the researchers have built a sorting machine for molecules, which can be used to selectively pick a conformer and feed it into a chemical reaction. The device exploits the fact that generally a change in structure also modifies the so-called dipole moment of a molecule. The dipole moment describes how a molecule interacts with an electric field. The sorting machine generates a non-uniform electric field between an electrically charged rod and a trough. When the researchers send several conformers at once through the narrow slit between the rod and the trough, the field deflects the various conformers to different degrees. The device thus provides sorted beams of different conformers, which can be spatially separated and directed individually into a reaction chamber.
As a test, the teams of Küpper and Willitsch sent two conformers of a well-known compound from the group of aminophenols through the device for sorting. Aminophenols are organic compounds that are used, among other things, for the production of medicines and dyes. The selected conformers differed only in the direction in which a single hydrogen atom is attached to an oxygen atom. "As a result, one conformer has a three times larger dipole moment than the other," says Küpper.
The scientists directed the various sorted beams alternately into a so-called ion trap developed in Basel, in which the two conformers would react with electrically charged calcium atoms (calcium ions). "In the ion trap, the calcium ions are cooled to almost absolute zero at a temperature of minus 273 degrees Celsius. Doing so, they arrange themselves in space and form an ideal target for reactions with the spatially separated conformers," says Willitsch.
"It turned out that one of the conformers has a reaction rate that is twice as high as that of the other," says team member Yuan-Pin Chang from CFEL. A tiny change in structure thus leads to big differences in chemical reactivity. "In this way, the method allows insights into fundamental reaction mechanisms that can lead to more effective syntheses of new molecules, such as active pharmaceutical ingredients," says Willitsch.
As a next step, the researchers want to improve the ion trap so that various ions and molecules could be used as reactants for sorted conformers. In addition, the trap will be combined with a mass spectrometer to determine the reaction products more accurately.
Original publication
Other news from the department science
![[Fe]-hydrogenase catalysis visualized using para-hydrogen-enhanced nuclear magnetic resonance spectroscopy](https://img.chemie.de/Portal/News/675fd46b9b54f_sBuG8s4sS.png?tr=w-712,h-534,cm-extract,x-0,y-16:n-xl)
These products might interest you
isoprime precisION by Elementar Analysensysteme
isoprime precisION stable isotope ratio mass spectrometer
The most flexible, yet powerful isotope ratio mass spectrometer ever created
IonTamer ToF MS by Spacetek Technology
IonTamer instruments are time-of-flight residual gas analysers (TOF-RGA) for the analysis of gases
Compact Time-of-flight residual gas analyzer (TOF-RGA) for process analysis
PlasmaQuant MS Elite by Analytik Jena
LC-ICP-MS Is the Key to the World of Elemental Species
Highest Sensitivity and Lowest Detection Limits with PlasmaQuant MS Series and PQ LC
HPR-20 OEMS, Online Electrochemical Mass Spectrometer by Hiden Analytical
Online monitoring and quantification of evolved gases and vapours from electrochemical processes
A complete gas analysis solution, designed to integrate seamlessly with electrochemical applications
NexION® 5000 by PerkinElmer
NexION 5000 Multi-Quadrupole ICP Mass Spectrometer
NexION 5000 Multi-Quadrupole ICP Mass Spectrometer
BIOS ANALYTIQUE - Soluciones de Renting y Leasing para laboratorios by Bios Analytique
Specialists in the rental and leasing of scientific equipment for laboratories throughout Europe
Whether you have an unexpected requirement or limited budget, we have the perfect solution for you
Xevo TQ Absolute by Waters
A new Tandem Quadrupole Mass Spectrometer for Quantification with Absolute power
Absolute performance, efficiency, productivity, and confidence for your most challenging compounds
iCAP RQ single Quadrupole ICP-MS by Thermo Fisher Scientific
Robust ICP-MS with ease of use and high productivity for routine analysis
A complete multi-element analysis solution for your high-throughput routine laboratory
iCAP TQ Triple Quadrupole ICP-MS by Thermo Fisher Scientific
Overcome unexpected interferences, reduce detection limits and improve data quality
Ultralow limits of detection with simplicity - even for the most challenging analytical applications
CATLAB Catalysis and Thermal Analysis by Hiden Analytical
A system for catalyst characterisation, kinetic and thermodynamic measurements
Integrated Microreactor-Mass Spectrometer for Reaction Testing, TPD/R/O and Pulse Chemisorption.
HPR-20 R&D by Hiden Analytical
A specialist benchtop triple filter mass spectrometer for the monitoring of evolved gases & vapours
Providing improved resolution & abundance sensitivity with an ultimate detection limit of 5 ppb sub
expression® Compact Mass Spectrometer by Advion Interchim Scientific
Mass Spectrometry for Chemists: Fast, Easy, Prep-Free Reaction Monitoring at the Bench
Featuring a variety of sample introduction techniques that also allow TLC/MS & direct probe analysis
JEOL JMS-T2000GC AccuTOF GC-Alpha Time-of-Flight Mass Spectrometer by JEOL
A new era of mass spectrometry for your fast forward daily lab routine:
Welcome JEOL AccuTOF GC-Alpha
Stop wrong hypotheses and uneconomic loops! Precise data without compromise is now.
Thermo Scientific TSQ Triple Quadrupole Mass Spectrometry Systems by Thermo Fisher Scientific
Confident quantitation with triple quadrupole LC-MS systems
Mass Spectrometry Systems
TSQ 9610 GC-MS/MS by Thermo Fisher Scientific
TSQ 9610 GC-MS/MS for superb sensitivity and selectivity with outstanding reliable productivity
Eliminate unnecessary, unplanned instrument downtime, save helium and maximize productivity
Orbitrap Exploris GC Mass Spectrometer by Thermo Fisher Scientific
Orbitrap Exploris GC-MS simplifies operations and offers new opportunities for analytical testing
Keep pace with changing demands, maximize system uptime, and expand laboratory capability.
Get the chemical industry in your inbox
From now on, don't miss a thing: Our newsletter for the chemical industry, analytics, lab technology and process engineering brings you up to date every Tuesday and Thursday. The latest industry news, product highlights and innovations - compact and easy to understand in your inbox. Researched by us so you don't have to.
Most read news
More news from our other portals
See the theme worlds for related content
Topic World Spectroscopy
Investigation with spectroscopy gives us unique insights into the composition and structure of materials. From UV-Vis spectroscopy to infrared and Raman spectroscopy to fluorescence and atomic absorption spectroscopy, spectroscopy offers us a wide range of analytical techniques to precisely characterize substances. Immerse yourself in the fascinating world of spectroscopy!
Topic World Spectroscopy
Investigation with spectroscopy gives us unique insights into the composition and structure of materials. From UV-Vis spectroscopy to infrared and Raman spectroscopy to fluorescence and atomic absorption spectroscopy, spectroscopy offers us a wide range of analytical techniques to precisely characterize substances. Immerse yourself in the fascinating world of spectroscopy!
